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/* LabS2LabQ()
*
* 17/11/93 JC
* - adapted from im_LabS2LabQ()
* 16/11/94 JC
* - adapted to new im_wrap_oneonebuf() function
* 15/6/95 JC
* - oops! rounding was broken
* 6/6/95 JC
* - added round-to-nearest
* - somewhat slower ...
* 21/12/99 JC
* - a/b ==0 rounding was broken
* 2/11/09
* - gtkdoc, cleanup
* 21/9/12
* - redo as a class
*/
/*
This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <vips/vips.h>
#include "pcolour.h"
typedef VipsColourCode VipsLabS2LabQ;
typedef VipsColourCodeClass VipsLabS2LabQClass;
G_DEFINE_TYPE( VipsLabS2LabQ, vips_LabS2LabQ, VIPS_TYPE_COLOUR_CODE );
/* Convert n pels from signed short to IM_CODING_LABQ.
*/
static void
vips_LabS2LabQ_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
{
signed short *p = (signed short *) in[0];
unsigned char *q = (unsigned char *) out;
int i;
for( i = 0; i < width; i++ ) {
int l, a, b;
unsigned char ext;
/* Get LAB, rounding to 10, 11, 11.
*/
l = p[0] + 16;
l = VIPS_CLIP( 0, l, 32767 );
l >>= 5;
/* Make sure we round -ves in the right direction!
*/
a = p[1];
if( a >= 0 )
a += 16;
else
a -= 16;
a = VIPS_CLIP( -32768, a, 32767 );
a >>= 5;
b = p[2];
if( b >= 0 )
b += 16;
else
b -= 16;
b = VIPS_CLIP( -32768, b, 32767 );
b >>= 5;
p += 3;
/* Extract top 8 bits.
*/
q[0] = l >> 2;
q[1] = a >> 3;
q[2] = b >> 3;
/* Form extension byte.
*/
ext = (l << 6) & 0xc0;
ext |= (a << 3) & 0x38;
ext |= b & 0x7;
q[3] = ext;
q += 4;
}
}
static void
vips_LabS2LabQ_class_init( VipsLabS2LabQClass *class )
{
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsColourClass *colour_class = VIPS_COLOUR_CLASS( class );
object_class->nickname = "LabS2LabQ";
object_class->description = _( "transform short Lab to LabQ coding" );
colour_class->process_line = vips_LabS2LabQ_line;
}
static void
vips_LabS2LabQ_init( VipsLabS2LabQ *LabS2LabQ )
{
VipsColour *colour = VIPS_COLOUR( LabS2LabQ );
VipsColourCode *code = VIPS_COLOUR_CODE( LabS2LabQ );
colour->coding = VIPS_CODING_LABQ;
colour->interpretation = VIPS_INTERPRETATION_LABQ;
colour->format = VIPS_FORMAT_UCHAR;
colour->input_bands = 3;
colour->bands = 4;
code->input_coding = VIPS_CODING_NONE;
code->input_format = VIPS_FORMAT_SHORT;
}
/**
* vips_LabS2LabQ:
* @in: input image
* @out: output image
* @...: %NULL-terminated list of optional named arguments
*
* Convert a LabS three-band signed short image to LabQ
*
* See also: vips_LabQ2LabS().
*
* Returns: 0 on success, -1 on error.
*/
int
vips_LabS2LabQ( VipsImage *in, VipsImage **out, ... )
{
va_list ap;
int result;
va_start( ap, out );
result = vips_call_split( "LabS2LabQ", ap, in, out );
va_end( ap );
return( result );
}
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